Japanese unexamined patent publication No. 2004-48925 discloses the following invention as a method of fixing a shaft and a rotor by caulking. FIGS. 20 and 21 illustrate Example 1 of a method for fixing a rotor 112 to a shaft 111 which method is disclosed in the publication '925. As shown in FIG. 20, the rotor 112 is disposed on a flange portion 111a of the shaft 111 and a fixing member 113 is disposed on the rotor 112. Further, a caulking jig 114 is disposed so as to be movable along a cutout portion 111d of a shaft portion 111c of the shaft 111. The inside diameter of a tip portion 114a is set larger than the outside diameter of the cutout portion 111d of the shaft 111 and smaller than the diameter of the shaft portion 111c of the shaft 111.
In such a construction, the caulking jig 114 is brought into abutment against a terminal end of the cutout portion 111d of the shaft 111, causing the caulking jig 114 and the shaft 111 to rotate relatively to each other. As a result, as shown in FIG. 21, a boundary portion between the shaft portion 111c of the shaft 111 and the cutout portion 111d is caulked by the caulking jig 11, whereby a protuberance 115 is formed. Consequently, the fixing member 113 is caulked fixedly to the shaft 111 by the protuberance 115.
FIGS. 22 and 23 illustrate Example 2 of the method for fixing a shaft and a rotor to each other by caulking which method is disclosed in the publication '925. As shown in FIG. 22, a rotor 112 is disposed on a flange portion 111a of a shaft 111 and a fixing member 113 is disposed on the rotor 112. Further, a caulking jig 116 is disposed so as to be movable along a shaft portion 111c of the shaft 111. The caulking jig 116 is formed with a tapered surface 116a. 
In such a construction, a load is applied in the axial direction of the rotor 112 under rotation of the caulking jig 116. As a result, the fixing member 113 is compressed with a load induced by the tapered surface 116a of the caulking jig 116, causing an upper end portion 113a in the figure of the fixing member 113 to get into a groove 111b of the shaft, 111, whereby the fixing member 113 is caulked fixedly to the shaft 111.